A liquid crystal lens achieves a focusing effect with a liquid crystal layer being driven by application of voltage. The smoother the distribution curve of the actual refractive index of the liquid crystal layer of the liquid crystal lens, the better the focusing property of the liquid crystal lens is. Therefore, the method of controlling the actual refractive index of the liquid crystal layer by application of voltage determines the image quality of the liquid crystal lens.
However, it is known to the inventor that liquid crystals are generally driven by using a multi-electrode method. In the multi-electrode method, because lateral voltages are generated at edges of electrodes, the refractive indexes, at the edges of the electrodes, of the liquid crystal molecules undergoes a large change, thus the spatial distribution curve of the refractive index of the liquid crystals becomes not smooth, and this causes the focusing property of the liquid crystal lens degraded.